Over the years a number of low fluid-loss systems, formulations, and application techniques have been developed for permanent-type well completions and in more recent times, for conventional wells. See in this connection, D. K. Smith, Cementing, Society of Petroleum Engineers of AIME, pub., New York and Dallas, 1976, and C. M. Stout and W. W. Wahl, Journal of Petroleum Technology, September 1960, pages 20-24, all disclosures of both of which are incorporated herein by reference.
Among the leading systems for controlling fluid loss in well cementing operations are systems based on polyalkylene polyamines, polyalkylene polyimines, and mixtures thereof. See for example Gibson et al U. S. Pat. No. 3,491,049; Scott et al U.S. Pat. No. 3,511,314; Crinkelmeyer et al U.S. Pat. No. 4,131,578; McKenzie U.S. Pat. No. 4,413,681; Spitz et al U.S. Pat. No. 4,482,381; and McKenzie et al, Oil & Gas Journal, March 1982, pages 146-148.
As pointed out in the Spitz et al '381 patent, the liquid polyamines of this type require addition of sulfonated polymers to provide effective fluid loss control. While such combinations do function to control fluid loss, they cause destabilization of the cement slurry. In order to ameliorate this problem the manufacturers of the polyalkylene polyamines and polyalkylene polyimines resorted to chemical modification of these polymers by cross-linking. Unfortunately the additional processing required increased the cost of the materials quite significantly.